Gaia theory: is it science yet?

what is gaia hypothesis

Honorary Senior Associate, Faculty of Science, The University of Melbourne

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Ian Enting does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

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what is gaia hypothesis

James Lovelock’s “ Gaia hypothesis ” has challenged conventional thinking about the nature of the earth as an integrated system. Gaia proposes that the earth acts like a living organism — that life is part of a self-regulating system, manipulating the physical and chemical environment to maintain the planet as a suitable home for life itself. Lovelock has developed this idea in a series of books, from “Gaia: A new look at life on earth” (1979) through to “Revenge of Gaia” (2006) and “The Vanishing Face of Gaia” (2009). He argues that as changes in the physical earth system occur, living systems respond so as to mitigate such changes.

How can a planet be alive?

In claiming that Gaia is “lifelike”, Lovelock notes the difficulty of defining life. He points out that a biological emphasis on (potential for) reproduction would, for example, exclude postmenopausal women. On the other hand, a physical emphasis on entropy reduction would include refrigerators. This leads Lovelock to emphasise physiological self-regulation as the defining characteristic of life-like systems - networks of interacting processes serve to regulate each other to preserve the functioning of the organism

what is gaia hypothesis

In discussing the concept of Gaia, Lovelock now distinguishes:

Gaia hypothesis : the original version — the Earth’s organisms regulate the physical and chemical components of the earth system so as to maintain the planet as an optimal habitat for life.

Gaia theory : the revision in response to critics — the combined physical, chemical and biological components of the earth system regulate the planet so as to maintain it as a habitat for life.

Various analyses have tried to distinguish between “weak” and “strong” Gaia, with weak Gaia differing little from conventional earth system science.

But isn’t Gaia for hippies?

The name Gaia has been widely used as a metaphor, as well co-opted for a large amount of pseudo-scientific baggage. This does not invalidate any underlying science any more than the majority of physics is invalidated by similar appropriation of terms such as “relativity”, “crystals”, “force fields” etc.

After stripping away such baggage, one has to confront the question: is what Lovelock is saying science and mysticism? While Lovelock has used the term “geophysiology” to avoid some of the mystical associations, he notes that all that has been achieved is that the term geophysiology now carries the same suspicion as the name Gaia.

what is gaia hypothesis

The confrontation between Gaian theory and “conventional” science is largely focused on a few key words: “Gaia is like a living organism … whose goal is to maintain the planet in state fit for life”.

A powerful argument against the Gaia hypothesis is the assertion (such as that made by Richard Dawkins in The Extended Phenotype ) that Gaia cannot arise from Darwinian evolution of life — the planet as a whole is not a unit of selection.

Dawkins can be answered by an anthropic argument (wherein observations of the physical universe must be compatible with the existence of the conscious life that observes it):

The emergence of Gaian self-regulation through the course of evolution is allegedly extremely improbable.

Nevertheless, the long-term survival of life on a planet without Gaian self-regulation may well be even more improbable.

Therefore, intelligent observers are most likely to find themselves on a planet with Gaian self-regulation.

Personally, I find this sort of argument unsatisfying. However, similar arguments seem to be needed to “explain” the physical universe — it is a very precise combination of physical constants that allows the existence of atoms heavier than hydrogen and helium. Anyway, if Gaian self-regulation has arisen by chance, one would still want to know how it works.

For me, one of the most intriguing possibilities is some form of “innate Gaia” — rather than being highly improbable, some degree of Gaian self-regulation is inevitable.

Writing in Nature Tim Lenton has proposed that if:

  • the physical system is stable, and
  • the biological system has self-increasing growth, and
  • there is a physical optimum for growth

then the steady state will be whichever side of the optimum leads to negative feedbacks, thus enhancing the stability of the physical system. The “optimal for life” in the original Gaia hypothesis is replaced by “mutually enhanced stability of the physical and biological systems”.

A theory with gaps is still a theory

While Thomas Henry Huxley famously talked of “the slaying of a beautiful hypothesis by an ugly fact” such discrepancies can also mean that the “ugly facts” are being misinterpreted.

For example, the gap in Wegener’s account of continental drift was that the continents aren’t ploughing through the crust — they are being carried by the crust. The gap in Darwin’s argument 150 years ago was the implicit assumption of blending of characteristics, so that new traits would be diluted. Mendel’s experiments showed that this is not so. Working out the details has been the work of subsequent generations of population geneticists.

what is gaia hypothesis

Returning to Dawkins’ argument as quoted above, the hidden assumption that may represent a weak point is the assumption of a single level of selection.

In Revenge of Gaia , Lovelock quotes William Hamilton: “Just as the observations of Copernicus needed a Newton to explain them, we need another Newton to explain how Darwinian evolution leads to a habitable planet.” This echoes Alfred Wegener: “The Newton of [continental] drift has not yet appeared. His absence need cause no anxiety.”

To summarise: gaps and discrepancies in a theory imply a case for serious further study, not necessarily a reason to panic and immediately abandon any consideration of the idea.

What does Gaia mean for humankind?

In his recent books, Lovelock argues that humanity is like an army with over-extended supply lines — there is no option but to retreat (allowing Gaia to recover). Depending on humanity’s choices the retreat could be comparable to the British from Dunkirk or Napoleon from Moscow. We can take control of population ourselves, or see it plummet as Gaia kills us off.

My interpretation of what Lovelock is proposing as the potential relation between Gaia and humanity is the 20th century concept of “Mutually Assured Destruction” rather than “revenge”.

These concerns seem to be based on Lovelock’s expectation of a third climate state. The last 500,000 years show an alternation between quasi-stable warm and cold states, flipping on a 100,000 year cycle.

Lovelock (using simple modelling described in Vanishing Face of Gaia) proposes that higher CO₂ will lead to a third, hotter, quasi-stable state. The proposed causal chain is: warming from more CO₂ → more stable oceans, less circulation → less nutrients at surface, so less algal production → less pumping of CO₂ into deep oceans → more CO₂ remains in the atmosphere, locking in the warming.

what is gaia hypothesis

But is there real evidence for a “third climate state”? Apart from the general principle that once self-regulation of a system fails, the failure can be very abrupt, are the arguments really Gaian?

So does it work?

An “ideal” summary would answer the question: “Is Lovelock right? Does the Gaia concept describe how the earth works?” I hope you won’t be too disappointed if I fail to commit to an answer. Indeed the whole process of preparing my talk and then editing it for The Conversation would have been less fun if I had been working from a preconceived view.

At times Lovelock seems to equate “Gaia” with “earth system science” by asking “would you have bought The Vanishing Face of Earth System Science?” A more substantive question is to ask: “is the (strong) Gaia concept established science?”, to which the answer is “not yet, and maybe it never will be”.

We come back to the statement that for Gaia “we need another Newton…”. Would a complete theory be a matter of filling in the gaps, as 150 years of accumulating evidence has “filled in the details” in Darwinian evolution? Or would the survival of Gaian theory mean morphing into something different, in the way that continental drift morphed into plate tectonics?

My best guess is that if “strong” Gaian theory survives (with or without the name Gaia) it will be through some such similar transformation. The “innate Gaia” implied by negative feedbacks being an “automatic” consequence of an interaction between expanding life and a dissipative physical system may well be part of such a re-synthesis.

Assessing Lovelock’s role as a “key thinker” raises the question of whether, regardless of its validity, the Gaia hypothesis has had a positive influence on the development of earth system science. (Lovelock’s other contributions to science through instrumentation have been invaluable). If, as I do not, one equates Gaia to current earth system science then the question largely disappears — the implication is that the rest of science has caught up with Lovelock.

My view is that even though “strong Gaia” and probably “innate Gaia” currently lie beyond the boundaries of established science, Lovelock’s role in pushing the boundaries of thinking about the earth system has spurred the thinking of many in the emerging earth system science community. This is a valuable legacy, regardless of the ultimate fate of his ideas.

This article is based on a lecture delivered in April 2009 as part of The University of Melbourne series of public lectures on Key Thinkers.

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  • 25 June 2019

James Lovelock at 100: the Gaia saga continues

  • Tim Radford 0

Tim Radford was science editor of The Guardian until 2005. As a science journalist, he met and got to know James Lovelock. His latest book is The Consolations of Physics .

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James Lovelock in his laboratory at home on the Devon–Cornwall border, UK

James Lovelock proposes that Earth will be saved by artificial intelligence. Credit: Tim Cuff/Alamy

Novacene: The Coming Age of Hyperintelligence James Lovelock Allen Lane (2019)

James Lovelock will always be associated with one big idea: Gaia. The Oxford English Dictionary defines this as “the global ecosystem, understood to function in the manner of a vast self-regulating organism, in the context of which all living things collectively define and maintain the conditions conducive for life on earth”. It cites the independent scientist as the first to use the term (ancient Greek for Earth) in this way, in 1972.

On 26 July, Lovelock will be 100; his long career has sparkled with ideas. His first solo letter to Nature — on a new formula for the wax pencils used to mark Petri dishes — was published in 1945. But, unusually for a scientist, books are his medium of choice. He has written or co-authored around a dozen; the latest, Novacene , is published this month.

As that book’s preface notes, Lovelock’s nomination to the Royal Society in 1974 listed his work on “respiratory infections, air sterilisation, blood-clotting, the freezing of living cells, artificial insemination, gas chromatography and so on”. The “and so on” briefly referred to climate science, and to the possibility of extraterrestrial life. The story of Gaia began with a question posed by NASA scientists while Lovelock was a consultant at the Jet Propulsion Laboratory in Pasadena, California. That is, how could you tell if a planet such as Mars harboured life?

what is gaia hypothesis

Final warning from a sceptical prophet

With microbiologist Lynn Margulis, Lovelock published a series of papers on the subject. In 1974, they developed a view of Earth’s atmosphere as “a component part of the biosphere rather than as a mere environment for life” ( J. E. Lovelock and L. Margulis Tellus 26 , 2–10; 1974 ). Earth’s atmosphere contains oxygen and methane — reactive gases, constantly renewed. That disequilibrium radiates an infrared signal, which Lovelock later described as an “unceasing song of life” that is “audible to anyone with a receiver, even from outside the Solar System”. Thus, the answer to NASA’s question was already written in the static Martian atmosphere, composed almost entirely of non-reactive carbon dioxide.

That was the beginning of a sustained and developing argument, in the face of sometimes dismissive criticism, that recast Earth as, in effect, a superorganism. Lovelock’s Gaia theory states that, for much of the past 3.8 billion years, a holistic feedback system has played out in the biosphere, with life forms regulating temperature and proportions of gases in the atmosphere to life’s advantage. Earth system science is now firmly established as a valuable intellectual framework for understanding the only planet known to harbour life, and increasingly vulnerable to the unthinking actions of one species. Colleagues and co-authors acknowledge that the argument continues, but endorse the importance of Lovelock and Margulis.

Entwined evolution

“The insight that the oceans and the atmosphere are thoroughly entwined with the living biosphere, and must be understood as a coupled system, has been completely vindicated,” says marine and atmospheric scientist Andrew Watson of the University of Exeter, UK. Lee Kump goes further. “Lovelock also showed us that Darwin had it only half right,” says Kump, a geoscientist at Pennsylvania State University in University Park. “Life evolves in response to environmental change, but the environment also evolves in response to biological change.” Despite severing formal links with universities decades ago, Lovelock has been showered with honorary degrees and awards from bodies as varied as NASA and the Geological Society of London.

The procession of engaging books began in 1979 with Gaia: A New Look at Life on Earth . Each volume made its case more forcefully than the last, exploring what was known first as the Gaia hypothesis, then simply as Gaia, and the hazards facing either the biosphere or humanity. The books include his endearing autobiography Homage to Gaia (2000), increasingly urgent warnings of climate devastation in The Revenge of Gaia (2006) and The Vanishing Face of Gaia (2009), and the less apocalyptic A Rough Ride to the Future (2014).

A black and white photo of James Lovelock standing in front of a row of bare trees.

James Lovelock pictured in 1989. Credit: Terry Smith/The LIFE Images Collection/Getty

Novacene picks up from that note of hope, and showcases another big idea. Gaia might, after all, be saved — by the singularity. This artificial-intelligence takeover, which so alarms many doomsayers, will be our redemption. Lovelock argues that increasingly self-engineering cyborgs with massive intellectual prowess and a telepathically shared consciousness will recognize that they, like organisms, are prey to climate change. They will understand that the planetary thermostat, the control system, is Gaia herself; and, in tandem with her, they will save the sum of remaining living tissue and themselves. The planet will enter the Novacene epoch: Lovelock’s coinage for the successor to the informally named Anthropocene.

Lovelock welcomes this. “Whatever harm we have done to the Earth, we have, just in time, redeemed ourselves by acting simultaneously as parents and midwives to the cyborgs,” he writes. He takes the long view on this rescue, however. Climate change is a real threat to humanity, but Earth will inevitably be overtaken by a ‘big heat’ in a few billion years, as the Sun slowly waxes more fierce.

Although co-authored with journalist Bryan Appleyard, Novacene reads like undiluted Lovelock. From the start of his writing life — no matter how tortuous the narrative or complex the argument — Lovelock has written persuasively. In his debut, Gaia , he sidestepped evolution’s first and biggest obstacle (how to get from organic chemistry to a living, devouring, excreting, replicating organism) in two sentences that seem to me models of clarity and brevity: “Life was thus an almost utterly improbable event with almost infinite opportunities of happening. So it did.”

what is gaia hypothesis

No place like home

In The Ages of Gaia (1988), a richer and more closely argued restatement, he answered the vexed question of how life contradicts the second law of thermodynamics. Life, he wrote, “has evolved with the Earth as a highly coupled system so as to favour survival. It is like a skilled accountant, never evading the payment of the required tax but also never missing a loophole.” This metaphoric brilliance is no rarity. A few pages on, he reminds us that Gaia is “a quarter as old as time itself. She is so old that her birth was in the region of time where ignorance is an ocean and the territory of knowledge is limited to small islands, whose possession gives a spurious sense of certainty.”

Lovelock’s Gaia theory is only one aspect of his nonconformism. His vigorous support for nuclear power annoys many environmentalists. Brought up as a Quaker, he registered as a conscientious objector in 1940, then changed his mind and prepared for military action in 1944 (the National Institute for Medical Research in London considered him more useful in the lab). Later, he became a consultant for the security services of Britain’s defence ministry. Among his inventions is an electron capture detector sensitive enough to identify vanishingly small traces of pollutants — such as the pesticides that spurred Rachel Carson to write the 1962 book Silent Spring — and chlorofluorocarbons, later implicated in damage to the ozone layer. In Novacene , he writes teasingly that he now sees himself as an engineer who values intuition above reason.

Lovelock to the last, he even has a kind word for the Anthropocene, marked by degradation of natural resources and the devastation of the wild things with which humanity evolved. He gives a “shout of joy, joy at the colossal expansion of our knowledge of the world and the cosmos”, and exults that the digital revolution ultimately “empowers evolution”. Is he right? Some of us might live to find out. In the meantime, if you want a sense of hyperintelligence in bipedal form, Novacene is a good place to start.

Nature 570 , 441-442 (2019)


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Who was James Lovelock, what is Gaia theory, and why does it matter today?

Science Who was James Lovelock, what is Gaia theory, and why does it matter today?

James Lovelock near a tree looking to the side

Australian climate scientist Andy Pitman only met James Lovelock once at a conference and remembers a "classic elderly, charming Englishman", but it's an image that belies nothing short of a revolutionary influence.

For someone like Professor Pitman, who studies the interaction of climate and vegetation, it's obvious that living things play a key role in regulating Earth's climate.

"If it wasn't for life, we would have cooked long ago, because life sucks the carbon dioxide out of the atmosphere into the land," says Professor Pitman, of the University of New South Wales.

The Earth is seen almost fully illuminated by the Sun against the pitch black of Space.

But when Professor Lovelock first went public with his idea that the   Earth was a giant organism that could regulate itself (including its climate) by using feedback between biological life and the rest of the planet, it was seen as rather radical.

"It was just so out there. It wasn't taken very seriously by many," Professor Pitman says.

But that was back in the 1970s — and today, even though many of Professor Lovelock's ideas remain controversial, his Gaia theory underpins a whole field of research called Earth systems science .

"I cannot overstate how profoundly transformative his contribution was," Professor Pitman says

"There are many people who think he has had more impact on our understanding of the Earth than any other singular scientist through the 20th century."

Life on Mars

Professor Lovelock, who died last week on his 103rd birthday , has been described as the "ultimate polymath" and a "connoisseur of nature" for whom "intuition and feeling" were just as important as science and data.

"My role has been to bring separated things and ideas together and make the whole more than the sum of the parts," he once told The Guardian .

James Lovelock at work in lab in 1960s

It all started back in the 1960s when Professor Lovelock, while working for NASA, designed an instrument to measure the chemical composition of Mars's atmosphere.

After comparing his measurements with those taken from Earth's atmosphere, he concluded there could be no life on the Red Planet.

Professor Lovelock argued the Martian atmosphere did not contain the signature balance of gases including oxygen, which is a sign of life on our planet.

"He basically was able to demonstrate without sending robots to Mars that there was no life there," Professor Pitman says.

The findings changed the way we understand Earth's atmosphere and its relationship to the rest of the planet.


In 1987, Professor Lovelock and colleagues proposed that phytoplankton in the ocean helps regulate the climate by giving off a gas, especially when it is sunny, which helps form clouds that shade the Earth, and bring rain that helps forests grow.

While scientists still debate how these cycles work , it was complex planet-scale interactions like this — involving biology as well as physics and chemistry, and the recycling of nutrients — that were key to Professor Lovelock's thinking.

Professor Pitman likens the feedback processes central to Gaia theory to what happens in our bodies to regulate temperature — we sweat when we're hot and shiver when we're cold.

He says Professor Lovelock's writings were "essential reading" for his own PhD back in the 1980s, and a vast amount of what we understand today is the result and direct consequence of such work.

Like minds with a planetary perspective

The idea of using the name Gaia — the Greek goddess who personifies the Earth — originally came from a chat with novelist William Golding of Lord of the Flies fame. And a Pentagon consultant by the name of Dian Hitchcock also appears on an early scientific paper of Professor Lovelock's.

But his key long-term intellectual collaborator was the evolutionary theorist, microbiologist and fellow maverick Lynn Margulis, who overturned our understanding of how life on Earth evolved.

James Lovelock and Lynn Margulis standing in the garden looking at camera

Professor Margulis also had a planetary perspective on things, says Bruce Clarke, of the Texas Tech University, who is a co-author of Writing Gaia, a new book that analyses 300 letters exchanged between professors Margulis and Lovelock between 1970 and 2007.

"She understood life as a global or planetary phenomenon," Professor Clarke says.

That's not surprising given that Professor Margulis was once married to cosmologist Carl Sagan, who knew Professor Lovelock, and suggested his wife connect with him.

"Lynn believed Gaia is run by the microbes," Professor Clarke says.

As well as collaborating on ideas, professors Lovelock and Margulis (who died in 2011) supported each other, in justifying their opposition to mainstream ideas, he adds.

And during the '70s and '80s it was them against scientists like Richard Dawkins, who was reducing life to a "molecular gene-centred vision" that made living organisms all "lumbering gene robots" at the mercy of their environment.

"For the longest time, Richard Dawkins was their mutual nemesis."

Gaia myths and climate prophecies

The fact that Gaia had mystical or spiritual connotations that resonated with many in the New-Age movement undermined Professor Lovelock's ideas in the eyes of some scientists.

So he spent a lot of time explaining that Gaia was not some kind of benevolent Earth mother, but it would take care of itself first, even if that wasn't great for humans.

As his collaborator Professor Margulis said: "Gaia is a tough bitch."

James Lovelock speaking publicly

Professor Lovelock is also well known for warning of the dire consequences of human activity pushing Gaia to the limit.

At the age of 86 he published a book called The Revenge of Gaia, which predicted destructive extreme weather from climate change would be the norm by 2020.

He even thought the COVID pandemic might be "a Gaian negative feedback mechanism to reduce human pressure on the Earth system".

At the same time, he argued humans were part of Gaia, and needed to use their consciousness to "give her a hand" to stave off the worst of climate change.

Professor Lovelock shocked many environmentalist fans, for example, by advocating the use of nuclear energy and then geoengineering as solutions to global warming.

His recipe for human salvation also included human retreat to megacities and artificial intelligence controlling the climate.

A free thinker

Whatever you think of James Lovelock, he will be remembered for being a truly independent scientist, which, Professor Pitman says, is "a very rare" thing in this day and age.

"He was a free thinker who thought outside the box … and had hard core scientific credentials."

Professor Lovelock was elected a Fellow of the Royal Society not long after his first paper on Gaia was published, and has received many other honours.

And it seems he was able to be so independent because he funded his own work, with the help of the income from no less than 40 patents from inventions he had created over the decades.

A device created in 1960 by James Lovelock called an electron capture device

These included the electron capture detector, which ended up detecting ozone-depleting chemicals.

Professor Lovelock's protégé, Tim Lenton, a professor of climate change and Earth systems science at the University of Exeter, believes his mentor's ideas on the interconnectedness of Earth's systems will help humans build a more sustainable future.

"He will go down in history as the person who changed our view of our place on Earth," Professor Lenton says.

"We need Jim's way of thinking now more than ever, if we are to get out of a climate and ecological crisis of our own making."

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"The Gaia hypothesis says that the temperature, oxidation state, acidity, and certain aspects of the rocks and waters are kept constant, and that this homeostasis is maintained by active feedback processes operated automatically and unconsciously by the biota." - James Lovelock, The Ages of Gaia

Suggested Readings:

  • Margulis, L and J. Lovelock. 1976. Is Mars a Spaceship, Too? Natural History , June/July pp. 86-90

In this lesson, we learn:

  • What are the weaknesses of the hypothesis? What are its strengths?
  • What are some examples of Gaia-like feedbacks?

Jump to: [ Introduction ] [ Origin of the Hypothesis ] [ Examples of Regulation ] [ Alternatives to Gaia ] [ Many Gain Hypotheses ] [ Summary ]

1. introduction - gaia and global change, 2. the hypothesis and its originators.

what is gaia hypothesis

3. Examples of Regulation of the Environment, According to Gaia

Perhaps life regulates the physical and chemical environment of the planet so as to maintain suitable planetary conditions for the good of life itself. If so, then the planet can be thought of as a single, integrated, living entity with self-regulating abilities. This is the radical view that Lovelock and Margulis have espoused. It can be thought of as the "strong Gaian model."

4. Alternatives to the Gaia Hypothesis

  • The idea that climate and life influence one another is profoundly important. In some form or another, it has been recognized for a long time. Life and climate "grew up together" and influenced one another over most of earth history. But this is not to say that life somehow manages and self-optimizes its own environment. It is this idea -- the "strong form of Gaia" -- that is most controversial.

5. The Many Gaian Hypotheses

" is unlikely that chance alone accounts for the fact that temperature, pH and the presence of compounds of nutrient elements have been, for immense periods, just those optimal for surface life. Rather, ... energy is expended by the biota to actively maintain these optima" (Lovelock and Margulis, 1974).

6. Modeling Gaia

You can model feedbacks using the classic Gaia example of Daisyworld with Stella or using this interactive Java applet .  The latter is especially useful to get a first-order understanding of changing parameters.  The Stella model permit more sophisticated analysis.

  • The hypothesis has been defined and argued in numerous ways, and has as many critics as adherents. It is in need of more explicit formulation before it can be examined and tested as a true scientific theory.  
  • Two models emerge: The model that life influences planetary processes (i.e., it has a substantial effect on abiotic processes) has become known as the weak Gaia hypothesis .  This model is widely supported. The original Gaia hypothesis, that life controls planetary processes (i.e., life created Earth's system), has become known as the strong Gaia hypothesis .  It is not widely accepted.

All materials © the Regents of the University of Michigan unless noted otherwise.

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One of the most unpredicted outcomes of the space program was the Gaia hypothesis, the theory the biosphere itself works to regulate the temperature and chemical content of the Earth’s atmosphere. According to Gaia theory, life is a planetary-wide phenomenon that alters the environment on a planetary scale.

Table of Planetary Atmospheres, after Lovelock, The Ages of Gaia .

When the Earth was formed billions of years ago, the atmosphere was almost entirely made out of carbon dioxide, just like Mars and Venus. But with the emergence of blue-green bacteria and photosynthesis, carbon dioxide became a life-giving food. In the alchemy of Earth’s primordial oceans, the living metabolism of bacteria transmuted carbon dioxide and other elements into an expanding tapestry of life. The metabolic activity of the first bacteria started to give birth to a planetary-wide physiology. These first blue-green bacteria removed carbon from the atmosphere, which cooled down the planet, and gave off oxygen as a waste product. But around two billion years ago, the process gave rise to a planetary crisis—an “oxygen holocaust”—when too much oxygen had accumulated. Oxygen itself was highly toxic to the first bacteria. [1] This planetary-wide crisis provided a window of opportunity, however, when a new type of blue-green bacteria finally learned to synthesize oxygen into life-energy. Over immense periods of time, the biosphere transformed the atmosphere into its present composition. The atmosphere so composed was an atmosphere friendly to life, both in terms of its content and its stable, hospitable temperature.

While other planetary scientists had supported a “Goldilocks theory”—assuming that the temperature and atmospheric composition of the Earth had been “just right” for the emergence of life by chance—Lovelock showed that life itself had altered the planetary environment. Lovelock proposed that “the evolution of the species and the evolution of their environment are tightly coupled together as a single and inseparable process,” [2] a claim that was supported by his colleague, the microbiologist Lynn Margulis. Moreover, Lovelock and Margulis claimed that Gaia was a testable, scientific hypothesis.

During the past 4.5 billion years, solar luminosity has increased by at least 10–30%. [3] But the Gaian superorganism has successfully maintained a steady temperature through its metabolic processes. When critics complained that Lovelock’s theory smacked of teleology or design, he created a simple computer model called Daisyworld. Daisyworld contains two types of daisies, white and black, that naturally live in a certain temperature range and absorb different levels of heat. If the temperature is low on Daisyworld, the black daisies flourish because they absorb more heat. This causes the planet to warm up. If the temperature is high on Daisyworld, the white daisies flourish and reflect heat back off into space. Even if the luminosity of Daisyworld’s sun increases substantially, Daisyworld itself maintains a constant temperature—until the environmental conditions caused by the solar warming become just too extreme for the biota to regulate. Lovelock had proven that life can act like a planetary thermostat, and more complex models with twenty shades of daisies produced the same result. [4]

In addition to holding the temperature constant by reducing carbon dioxide, life has regulated the amount of oxygen in the atmosphere. Right now oxygen makes up 21% of the atmosphere, a level that must have remained constant for over 300 million years. If the concentration of oxygen was just a few points higher, devastating forest fires would engulf the planet. But if the oxygen level was a few points lower, animal life would perish.

As biologist Lynn Margulis points out, “life does not exist on Earth’s surface so much as it is Earth’s surface. . . . Earth is no more a planet-sized chunk of rock inhabited with life than your body is a skeleton infested with cells.” [5] Gaia’s radical challenge to traditional Darwinian biology is that life influences the environment. For Darwin, life was essentially passive, a process that was forced to adapt to a specific environment. Gaia theory shows that life and environment evolve as a single, coevolutionary process. On Earth, all life is an embodiment of the planetary environment, but the planetary environment is also product of life. Gaia theory and the new biology embodies the circular, metabolic logic of life. The universe brings forth life and mind—but life and mind work to shape the universe. Life and environment are folded back on themselves in a self-referential, evolutionary spiral. Gaia is not a single organism, but a superorganism. Like the single organisms of which it is comprised, it is self-regulating and autopoietic. Like my own body composed of many individual cells, Gaia has its own metabolism. As we breathe and exhale, we participate in the life-breath of the entire biosphere. Gaia theory is strongly supported by complexity science, which shows how complex systems with feedback loops spontaneously self-organize and develop metabolic patterns. From the Gaian perspective, our own lives are totally inseparable from the life of the larger planet.

[1] For a discussion of the oxygen holocaust, see chapter six in Margulis and Sagan, Microcosmos: Four Billion Years of Microbial Evolution (Berkeley: University of California Press, 1997) .

[2] James Lovelock, The Ages of Gaia (New York: W. W. Norton, 1988), 18. As he writes, “Through Gaia theory I now see the system of the material Earth and the living organisms on it, evolving so that self-regulation is an emergent property. In such a system active feedback processes operate automatically and solar energy sustains comfortable conditions for life. The conditions are only constant in the short term and evolve in synchrony with the changing needs of the biota as it evolves. Life and its environment are so closely couple that evolution concerns Gaia, not the organisms or the environment taken separately” (19–20).

[3] M. Newman, “Evolution of the Solar Constant,” in C. Ponnamperuma and Lynn Margulis, editors, Limits to Life (Dordrecht: D. Reidel, 1980) . See also Lawrence Joseph, Gaia: The Growth of an Idea (New York: St. Martin’s Press, 1990), 121–25.

[4] See Lovelock, The Ages of Gaia, chapter 3.

[5] Margulis and Sagan, What is Life? (New York: Simon and Schuster, 1999), 28.

Reprinted from chapter 11 of  Restoring the Soul of the World: Our Living Bond with Nature’s Intelligence by David Fideler. Copyright © 2014 by David Fideler. All rights reserved. May not be reproduced in any form without the written permission of the author.

“Viewed from the distance of the moon, the astonishing thing about the earth, catching the breath, is that it is alive. The photographs show the dry, pounded surface of the moon in the foreground, dead as an old bone. Aloft, floating free beneath the moist, gleaming membrane of the bright blue sky, is the rising earth, the only exuberant thing in this part of the cosmos. If you could look long enough, you would see the swirling of the great drifts of white cloud, covering and uncovering the half-hidden masses of land. If you had been looking a very long, geologic time, you could have seen the continents themselves in motion, drifting apart on their crustal plates, held aloft by the fire beneath. It has the organized, self-contained look of a live creature, full of information, marvelously skilled in handling the sun.” — Lewis Thomas, The Lives of a Cell

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What is the Gaia hypothesis introduced by James Lovelock?

what is gaia hypothesis

Leading environmental scientist and creator of the Gaia hypothesis James Lovelock has died on his 103rd birthday .

The climate scientist died at home on Tuesday surrounded by loved ones, his family said. The world-renowned scientist had been in good health until six months ago when he had a bad fall.

His family said: “Our beloved James Lovelock died yesterday in his home surrounded by his family on his 103rd birthday. To the world he was best known as a scientific pioneer, climate prophet and conceiver of the Gaia theory. To us he was a loving husband and wonderful father with a boundless sense of curiosity, a mischievous sense of humour and a passion for nature.

“Up until six months ago he was still able to walk along the coast near his home in Dorset and take part in interviews, but his health deteriorated after a bad fall earlier this year. He passed away at 9.55pm of complications related to the fall. The funeral will be private. There will be a public memorial service later. The family requests privacy at this time.”

Mr Lovelock was best known for his Gaia hypothesis which posits that the Earth acts as a self-regulating organism made up of all its life forms, which humans are severely damaging. He said two years ago that the biosphere was in the last 1% of its life.

Known as a maverick, Lovelock dispensed predictions from his one-man laboratory since the mid-1960s, and in his old age he continued to work.

Here’s everything you need to know about James Lovelock’s Gaia hypothesis.

What is James Lovelock’s Gaia hypothesis?

what is gaia hypothesis

James Lovelock’s Gaia hypothesis is named after the ancient Greek goddess of Earth, and it posits that Earth and its biological systems behave as a huge single entity.

The theory was first conceived in the 1970s by Lovelock and the biologist Lynn Margulis.

The Earth’s entity has a closely-controlled self-regulatory negative feedback loop, that keeps the conditions on the planet within boundaries that are favourable to supporting life.

The Lovelock hypothesis offers a new way to look at global ecology, which differs from the classical picture stating that ecology is a biological response to a list of physical conditions.

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The idea that biology and the physical environment co-evolve and influence one another was first suggested as early as the mid-1700s, however, the link was never made as clearly as with Gaia, which states that biology controls the non-living environment, too.

What are the main observations underpinning the Gaia hypothesis?

The Gaia hypothesis states that the Earth’s surface is maintained in a habitable state by self-regulating feedback mechanisms involving organisms that are closely related and tightly coupled to their environment.

The concept is based on several observations:

  • The atmosphere is in extreme thermodynamic disequilibrium owing to the activities of life, yet aspects of its composition are remarkably stable.
  • Present conditions at the surface of the Earth are close to optimal for dominant organisms.
  • Life has persisted for over 3.8 billion years despite increasing solar luminosity.
  • The Earth system has repeatedly recovered from massive perturbations.

Who was James Lovelock?

Lovelock was born in 1919 in Letchworth Garden City, Herefordshire, and studied chemistry, medicine and biophysics in the UK and the US.

He worked at the Medical Research Council, and then in the 1960s on Nasa’s moon and Mars programmes at the Jet Propulsion Laboratory in Pasadena, California.

Throughout his career, he was a leading voice on climate change , as well as an inventor whose creations included a highly sensitive electron capture detector that tracks pollutants including ozone-depleting CFCs (chlorofluorocarbons).

Dame Mary Archer, chair of the Science Museum Group’s board of trustees, said: “Arguably the most important independent scientist of the last century, Jim Lovelock was decades ahead of his time in thinking about the Earth and climate and his unique approach was an inspiration for many.

“Originality of thought, scepticism of the status quo and above all a focus on invention lie at the heart of his remarkable contribution to science.”

Roger Highfield , science director at the museum, said: “Jim was a non-conformist who had a unique vantage point that came from being, as he put it, half scientist and half inventor.

“Endless ideas bubbled forth from this synergy between making and thinking.

“Although he is most associated with Gaia, he did an extraordinary range of research, from freezing hamsters to detecting life on Mars, popularised his ideas in many books, and he was more than happy to bristle a few feathers, whether by articulating his dislike of consensus views, formal education and committees, or by voicing his enthusiastic support for nuclear power.”

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  • Gaia Hypothesis


What is Gaia Hypothesis?

Gaia hypothesis can also be referred to as Gaia theory or Lovelock Gaia because it was conceived and introduced to the world by a chemist, James E. Lovelock in the early 1970s. The James Lovelock Gaia hypothesis provides a newer perspective to look at the global ecology and its evolution. The Gaia model was formed by James E. Lovelock and biologist Dr. Lynn Margulis. It is different from the traditional portrayal of ecology, which presents it as a consequence of a biological response to the classical menu of physical conditions. 

Meaning of Gaia Hypothesis 

Gaia hypothesis meaning can be understood by the Gaia hypothesis definition that can be stated as an interaction between living organisms on the Earth with their inorganic surroundings forming a complex, self-regulating and synergistic system that helps perpetuate and maintain optimum conditions for life on the planet. 

It was hypothesized that by using the Gaia principle one can detect life in the atmosphere of other planets. The Gaia theory of James Lovelock was a relatively cheaper and reliable way to use such interactive combinations to find the possibility of life on planets other than the Earth. 

Initial Gaia Hypothesis 

The initial Gaia hypothesis states that the Earth has maintained its habitable state through a self-regulating feedback loop that is automatically carried out by the living organisms that are tightly coupled to their respective environments. The observations made in the James Lovelock Gaia Hypothesis were: 

Despite an increase in energy provided by the sun, the earth’s global surface temperature has been constant. 

Owing to the activities of life of the living organisms, the atmosphere is in an extreme state of disequilibrium of thermodynamics and yet the aspects of its composition are astoundingly stable. Even with so many atmospheric components of varying degrees like 20.7 percent of oxygen, 79 percent of nitrogen, traces of methane, and 0.03 percent of carbon dioxide, the atmospheric composition remains constant rather than unstable.

Constant ocean salinity for a very long time can be contributed to the seawater circulation via the hot basaltic rocks that emerge on ocean spreading ridges as hot water vents. 

The earth system has consistently and continuously recovered from massive perturbations owing to its self-regulation complex process. 

James Lovelock views this entirety of complex processes on the Earth’s surface as one, to maintain suitable conditions for life. The earthly processes from its formation to its disturbances, eruptions, and recovery is all considered to be one self-regulating system. 

Criticisms and Refinements of the Gaia Hypothesis

The Gaia theory named after the Greek Goddess Gaia, which represents the Earth was however heavily criticized initially against the natural selection principles proposed by Charles Darwin. The other criticism of the Gaia theory was its teleological nature of stating finality and not the cause of such occurrences in Lovelock Gaia. The refined Gaia hypothesis that aligned the Gaia model with the production of sulfur and iodine by sea creatures in quantities approximately required by the land creatures that supported and made the Gaia theory stating interactions stronger that bolster the hypothesis. 

Arguments and Criticism

The theory and hypothesis were criticized due to the following reasons.

The significant increase in global surface temperatures contradicts the observatory comment according to the theory. 

Salinity in the ocean is far from being at constant equilibrium as river salts have raised the salinity. 

The self-regulation theory is also disregarded as evidence against it was surfaced by reduced methane levels and oxygen shocks during the various ice ages that are during the Huronian, Sturtian, and Marinoan or Varanger Ice Ages. 

Dimethyl sulfide produced by the phytoplankton plays an important role in climate regulation and the process does not happen on its own as stated by James Lovelock. 

Another claim that stated the Gaia theory is contradictory to the Natural Selection theory and is far from the survival of the fittest theory that was the greatest diversion according to Lovelock’s theory. 

The other criticisms stated that Gaia had four hypotheses and not just one.

(a) Coevolutionary Gaia stated the environment and the life in it evolved in a  coupled way that was criticized stating Gaia theory is only claiming that it has already been a scientifically accepted theory.

(b) Homeostatic Gaia stated that the stability of the natural environment is maintained by life and that stability enables life to exist disregarded stating it was not scientific because it was untestable.

(c) The Geophysical Gaia hypothesis stated new geophysical cycles that only aroused curiosity and piqued interest in researching the terrestrial geographical dynamics. 

(d) The optimizing Gaia hypothesis was also disregarded because of its untestability and therefore unscientific nature that stated the planet shaped by Gaia made life for the environment as a whole. 

Daisyworld Simulations

The refined New Gaia hypothesis was a counter-argument by James Lovelock. Lovelock along with Andrew Watson developed a new model that is the Daisyworld Simulations which is a mathematical model. Daisyworld is to be considered a planet where only daisies grow and there are black daisies and white daisies. The conditions in the Daisyworld are in many respects similar to that of the Earth.

Water and nutrients are abundant in Daisyworld for the daisies.

The ability to grow and for the daisies to spread across this imaginary planet’s surface depends entirely on the temperature.

The climate system in Daisyworld is simple with no greenhouse gases and clouds.

The planetary incident light and radiation that affects the surface temperature depends on the aerial coverage of the grey soil by the white and black daisies. 

In this model, the planetary temperature regulation is underpinned by ecological competition by examining the energy budget which is the energy provided by the sun and with high energy temperature increases, and with low energy the temperature decreases. 

[Image will be uploaded soon]

The graphical presentation of the Daisyworld simulations shows it is parabolic with minimum temperature, optimum temperature, and maximum growth temperature. 

The albedo that is the reflection and the absorption of light is influenced by the colour of daisies. 

Light- The black daisies warm the Daisyworld by absorbing more light and white daisies cool the planet by reflecting more light.

Growth-  Black daisies grow and reproduce best at temperatures relatively lower than the white daisies that thrive at a higher temperature.

When the temperature rises Daisyworld’s surface is filled with more white daisies that reduce heat input and consequently cooling the planet. For instance in figure 3 given below.

With the decline in temperatures, the scenario in figure 2 takes place wherein the white daisies are outnumbered by the black daisies making the planet warmer by increasing absorption of the energy provided by the sunlight. 

Plant reproduction becomes equal when temperatures converge to the value of both their reproductive rates, both will thrive as shown in figure 1.

Result of The Refined Gaia Hypothesis

The Gaia hypothesis through the Daisyworld simulations proved that the percentage of black daisies in comparison to white ones will continuously change so both could thrive. This further shows that competition and even with a limited range of conditions like on the planet Daisyworld can also support life with stabilized temperatures. In other words, if the sun’s energy output changes the temperature of the planet will greatly vary due to wide and different degrees of albedo. 

Gaia Hypothesis Summary 

The Gaia hypothesis has had its fair share of criticism because of its need for more explicit formulation and consequently it being untestable and hence not scientifically proven. Even with this through the years various modifications have been done and via these two models of Gaia emerges the weak Gaia hypothesis that suggests the planetary processes are substantially influenced by the life on the planet which is widely supported. The other model is known as the strong Gaia hypothesis that states that life creates the earth’s systems in other words planetary processes are controlled by life which is not supported and widely accepted. 


FAQs on Gaia Hypothesis

1. Is the Gaia Hypothesis No Longer Valid?

Ans. When initially presented by James E. Lovelock, the Gaia hypothesis was heavily criticized, and scientists and biologists were apprehensive of considering it to be valid.  With researches and findings over the years since its inception, the idea of Gaia being full of homeostasis is not valid due to the Gaia hypothesis one has been able to research and find out stronger evidence that aligns with the Gaia model. For instance, the fact that living alone is not responsible for the equilibrium, it is the entire ecosystem or the Earth system that works in stabilizing the life process which allows life to exist and thrive. 

2. Has the Gaia Hypothesis Been Accepted?

Ans. The Gaia hypothesis has since been supported by several scientific experiments through which one was able to make several useful predictions. The original hypothesis was wrong and discarded but the newer models that are known as the weak Gaia hypothesis have been accepted and widely supported. The acceptance of the Gaia hypothesis has not been widely acknowledged yet and one is constantly researching and finding shreds of evidence to either support or disregard it.

3. What are the Uses of the Gaia Principle?

Ans. The Gaia theory predicted the causal link between increased biodiversity and contrary to the popular belief of it contradicting the natural selection theory the Gaia principle supported it by drawing connections with increasing stability of populations. The Gaian influence furthermore solidifies the evolutionary theory development of the fact that be found in the idea that life on the earth can be considered to be in works with the abiotic environment as a self-regulatory system and both contribute to making the planet a place for stability and constant growth.

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Environment and Ecology

environment - ecology - nature - habitat - gaia - permaculture - systems - sustainability ...

Gaia Hypothesis

The Gaia hypothesis was first scientifically formulated in the 1960s by the independent research scientist James Lovelock, as a consequence of his work for NASA on methods of detecting life on Mars. [4] [5] He initially published the Gaia Hypothesis in journal articles in the early 1970s [6] [7] followed by a popularizing 1979 book Gaia: A new look at life on Earth .

The theory was initially, according to Lovelock, a way to explain the fact that combinations of chemicals including oxygen and methane persist in stable concentrations in the atmosphere of the Earth. Lovelock suggested using such combinations detected in other planets' atmospheres would be a relatively reliable and cheap way to detect life, which many biologists opposed at the time and since. Later other relationships such as the fact that sea creatures produce sulfur and iodine in approximately the quantities required by land creatures emerged and helped bolster the theory. Rather than invent many different theories to describe each such equilibrium, Lovelock dealt with them holistically, naming this self-regulating living system after the Greek goddess Gaia, using a suggestion from the novelist William Golding, who was living in the same village as Lovelock at the time (Bowerchalke, Wiltshire, UK). The Gaia Hypothesis has since been supported by a number of scientific experiments [8] and provided a number of useful predictions, [9] and hence is properly referred to as the Gaia Theory.

Since 1971, the noted microbiologist Dr. Lynn Margulis has been Lovelock's most important collaborator in developing Gaian concepts. [10]

Until 1975 the hypothesis was almost totally ignored. An article in the New Scientist of February 15, 1975, and a popular book length version of the theory, published in 1979 as The Quest for Gaia , began to attract scientific and critical attention to the hypothesis. The theory was then attacked by many mainstream biologists. Championed by certain environmentalists and climate scientists, it was vociferously rejected by many others, both within scientific circles and outside them.

Lovelock's initial hypothesis

James Lovelock defined Gaia as:

His initial hypothesis was that the biomass modifies the conditions on the planet to make conditions on the planet more hospitable – the Gaia Hypothesis properly defined this "hospitality" as a full homeostasis. Lovelock's initial hypothesis, accused of being teleological by his critics, was that the atmosphere is kept in homeostasis by and for the biosphere.

Lovelock suggested that life on Earth provides a cybernetic, homeostatic feedback system operated automatically and unconsciously by the biota, leading to broad stabilization of global temperature and chemical composition.

With his initial hypothesis, Lovelock claimed the existence of a global control system of surface temperature, atmosphere composition and ocean salinity. His arguments were:

  • The global surface temperature of the Earth has remained constant, despite an increase in the energy provided by the Sun.
  • Atmospheric composition remains constant, even though it should be unstable.
  • Ocean salinity is constant.

Since life started on Earth, the energy provided by the Sun has increased by 25% to 30%; [11] however the surface temperature of the planet has remained remarkably constant when measured on a global scale. Furthermore, he argued, the atmospheric composition of the Earth is constant. [12] The Earth's atmosphere currently consists of 79% nitrogen, 20.7% oxygen and 0.03% carbon dioxide. Oxygen is the second most reactive element after fluorine, and should combine with gases and minerals of the Earth's atmosphere and crust. Traces of methane (at an amount of 100,000 tonnes produced per annum) [13] should not exist, as methane is combustible in an oxygen atmosphere. This composition should be unstable, and its stability can only have been maintained with removal or production by living organisms.

Ocean salinity has been constant at about 3.4% for a very long time. [14] Salinity stability is important as most cells require a rather constant salinity and do not generally tolerate values above 5%. Ocean salinity constancy was a long-standing mystery, because river salts should have raised the ocean salinity much higher than observed. Recently it was suggested [15] that salinity may also be strongly influenced by seawater circulation through hot basaltic rocks, and emerging as hot water vents on ocean spreading ridges. However, the composition of sea water is far from equilibrium, and it is difficult to explain this fact without the influence of organic processes.

The only significant natural source of atmospheric carbon dioxide (CO 2 ) is volcanic activity, while the only significant removal is through the precipitation of carbonate rocks. [16] In water, CO 2 is dissolved as a "carbonic acid," which may be combined with dissolved calcium to form solid calcium carbonate (limestone). Both precipitation and solution are influenced by the bacteria and plant roots in soils, where they improve gaseous circulation, or in coral reefs, where calcium carbonate is deposited as a solid on the sea floor. Calcium carbonate can also be washed from continents to the sea where it is used by living organisms to manufacture carbonaceous tests and shells. Once dead, the living organisms' shells fall to the bottom of the oceans where they generate deposits of chalk and limestone. Part of the organisms with carbonaceous shells are the coccolithophores (algae), which also have a role in the formation of clouds. When they die, they release dimethyl sulfide gas (DMS), (CH 3 ) 2 S, which is converted by atmospheric processes to sulfate particles on which water vapor condenses to make clouds. [17]

Lovelock sees this as one of the complex processes that maintain conditions suitable for life. The volcanoes produce CO 2 in the atmosphere, CO 2 participates in rock weathering as carbonic acid, itself accelerated by temperature and soil life, the dissolved CO 2 is then used by the algae and released on the ocean floor. CO 2 excess can be compensated by an increase of coccolithophoride life, increasing the amount of CO 2 locked in the ocean floor. Coccolithophorides increase the cloud cover, hence control the surface temperature, help cool the whole planet and favor precipitations which are necessary for terrestrial plants. For Lovelock and other Gaia scientists like Stephan Harding, coccolithophorides are one stage in a regulatory feedback loop. Lately the atmospheric CO 2 concentration has increased and there is some evidence that concentrations of ocean algal blooms are also increasing. [18]

Controversial concepts

Lovelock, especially in his older texts, used language that has later caused fiery debate. For instance, many of his biological critics such as Stephen Jay Gould and Richard Dawkins attacked his statement in the first paragraph of his first Gaia book (1979), that "the quest for Gaia is an attempt to find the largest living creature on Earth." [19]

Lynn Margulis, the coauthor of Gaia hypotheses, is more careful to avoid controversial figures of speech than is Lovelock. In 1979 she wrote, in particular, that only homeorhetic and not homeostatic balances are involved: that is, the composition of Earth's atmosphere, hydrosphere, and lithosphere are regulated around "set points" as in homeostasis, but those set points change with time. Also she wrote that there is no special tendency of biospheres to preserve their current inhabitants, and certainly not to make them comfortable. Accordingly, the Earth is a kind of community of trust which can exist at many discrete levels of integration. This is true for all multicellular organisms which do not live or die all at once: not all cells in the body die instantaneously, nor are homeostatic "set points" constant through the life of an organism.

Critical analysis

This theory is based on the idea that the biomass self-regulates the conditions on the planet to make its physical environment (in particular temperature and chemistry of the atmosphere) on the planet more hospitable to the species which constitute its "life". The Gaia Hypothesis properly defined this "hospitality" as a full homeostasis. A model that is often used to illustrate the original Gaia Hypothesis is the so-called Daisyworld simulation.

Whether this sort of system is present on Earth is still open to debate. Some relatively simple homeostatic mechanisms are generally accepted. For example, when atmospheric carbon dioxide levels rise, the biomass of photosynthetic organisms increases and thus removes more carbon dioxide from the atmosphere, but the extent to which these mechanisms stabilize and modify the Earth's overall climate are not yet known. Less clear is the reason why such traits should evolve in a system in order to produce such effects. Lovelock accepts a process of systemic Darwinian evolution for such mechanisms, creatures that evolve that improve their environment for their survival will do better than those which damage their environment. But many scientists do not believe such mechanisms exist. [20]

After initially being largely ignored by most scientists, (from 1969 until 1977), thereafter for a period, the initial Gaia hypothesis was ridiculed by a number of scientists, like Ford Doolittle, Dawkins and Gould. Lovelock has said that by naming his theory after a Greek goddess, championed by many non scientists [1] , the Gaia hypothesis was derided as some kind of neo-Pagan New Age religion. Many scientists in particular also criticised the approach taken in his popular book "Gaia, a New look at Life on Earth" for being teleological; a belief that all things have a predetermined purpose. Lovelock seems to have accepted this criticism of some of his statements, and has worked hard to remove the taint of teleological thinking from his theories, stating "Nowhere in our writings do we express the idea that planetary self-regulation is purposeful, or involves foresight or planning by the biota." – (Lovelock, J. E. 1990).

In 1981, W. Ford Doolittle, in the CoEvolution Quarterly article "Is Nature Motherly" argued that there was nothing in the genome of individual organisms which could provide the feedback mechanisms Gaia theory proposed, and that therefore the Gaia hypothesis was an unscientific theory of a maternal type without any explanatory mechanism. In Richard Dawkins' 1982 book, The Extended Phenotype , he argued that organisms could not act in concert as this would require foresight and planning from them. Like Doolittle he rejected the possibility that feedback loops could stabilize the system. Dawkins claimed "there was no way for evolution by natural selection to lead to altruism on a Global scale".

Stephen Jay Gould criticised Gaia as merely a metaphorical description of Earth processes [21] . He wanted to know the actual mechanisms by which self-regulating homeostasis was regulated. Lovelock argues that no one mechanism is responsible, that the connections between the various known mechanisms may never be known, that this is accepted in other fields of biology and ecology as a matter of course, and that specific hostility is reserved for his own theory for political reasons.

Aside from clarifying his language and understanding of what is meant by a life form, Lovelock himself ascribes most of the criticism to a lack of understanding of non-linear mathematics by his critics, and a linearizing form of greedy reductionism in which all events have to be immediately ascribed to specific causes before the fact. He notes also that his theory suggests experiments in many different fields, but few of them in biology which most of his critics are trained in. "I'm a general practitioner in a world where there's nothing but specialists... science in the last two centuries has tended to be ever-dividing" and often rivalrous, especially for funding which Lovelock describes as overly abundant and overly focused on institutions rather than original thought. He points out that Richard Feynman not only shared this opinion (coining the term cargo cult science) but also accepted a lack of general cause and effect explanation as an inevitable phase in a theory's development, and believed that some self-regulating phenomena may not be explainable at all mathematically.

One of the criteria of the empirical definition of life is its ability to replicate and pass on their genetic information to succeeding generations. Consequently, an argument against the idea that Gaia is a "living" organism is the fact that the planet is unable to reproduce.

Lovelock, however, defines life as a self-preserving, self-similar system of feedback loops like Humberto Maturana's autopoiesis; as a self-similar system, life could be a cell as well as an organ embedded into a larger organism as well as an individual in a larger inter-dependent social context. The biggest context of interacting inter-dependent living entities is the Earth. The problematic empirical definition is getting "fuzzy on the edges": Why are highly specialized bacteria like E. coli that are unable to thrive outside their habitat considered "life", while mitochondria, which have evolved independently from the rest of the cell, are not?

Maturana and Lovelock changed this with the autopoiesis deductive definition which to them explains the phenomenon of life better; some aspects of the empirical definition, however, no longer apply. Reproduction becomes optional: bee swarms reproduce, while the biosphere has no need to. Lovelock himself states in the original Gaia book that even that is not true; given the possibilities, the biosphere may multiply in the future by colonizing other planets, as humankind may be the primer by which Gaia will reproduce. Humanity's exploration of space, its interest in colonizing and even terraforming other planets, lends some plausibility to the idea that Gaia might in effect be able to reproduce.

The astronomer Carl Sagan also remarked that from a cosmic viewpoint, the space probes since 1959 have the character of a planet preparing to go to seed [22] . This might warrant interpretation as a rhetorical point, however, as it equivocates two differing meanings of "reproduction" otherwise.

Daisyworld simulations

Lovelock responded to criticisms by developing the mathematical model Daisyworld with Andrew Watson to demonstrate that feedback mechanisms could evolve from the actions or activities of self-interested organisms, rather than through classic group selection mechanisms. [23]

Daisyworld examines the energy budget of a planet populated by two different types of plants, black daisies and white daisies. The colour of the daisies influences the albedo of the planet such that black daisies absorb light and warm the planet, while white daisies reflect light and cool the planet. Competition between the daisies (based on temperature-effects on growth rates) leads to a balance of populations that tends to favour a planetary temperature close to that which is optimum for the daisy growth. Lovelock and Watson demonstrated the stability of Daisyworld by forcing the sun that it orbits to evolve along the main sequence, taking it from low to high solar constant. This perturbation of Daisyworld's receipt of solar radiation caused the balance of daisies to gradually shift from black to white but the planetary temperature was always regulated back to this optimum (except at the extreme ends of solar evolution). This situation is very different from the corresponding abiotic world, where temperature is unregulated and rises linearly with solar output. Later versions of Daisyworld introduced a range of grey daisies and populations of grazers and predators, and found that these further increased the stability of the homeostasis. More recently other research, modelling the real biochemical cycles of Earth, and using various "guilds" of life (eg. photosynthesisers, decomposers, herbivores and primary and secondary carnivores) has also been shown to produce Daisyworld-like regulation and stability, which helps to explain planetary biological diversity.

This enables nutrient recycling within a regulatory framework derived by natural selection amongst species, where one being's harmful waste becomes low energy food for members of another guild. This research on the Redfield ratio of Nitrogen to Phosphorus shows that local biotic processes can regulate global systems (See Keith Downing & Peter Zvirinsky, The Stimulated Evolution of Biochemical Guilds: Reconciling Gaia Theory with Natural Selection ).

First Gaia conference

In 1988, to draw attention to the Gaia hypothesis, the climatologist Stephen Schneider organised a conference of the American Geophysical Union's first Chapman Conference on Gaia, held at San Diego in 1989, solely to discuss Gaia.

At the conference James Kirchner criticised the Gaia hypothesis for its imprecision. He claimed that Lovelock and Margulis had not presented one Gaia hypothesis, but four -

  • CoEvolutionary Gaia — that life and the environment had evolved in a coupled way. Kirchner claimed that this was already accepted scientifically and was not new.
  • Homeostatic Gaia — that life maintained the stability of the natural environment, and that this stability enabled life to continue to exist.
  • Geophysical Gaia — that the Gaia theory generated interest in geophysical cycles and therefore led to interesting new research in terrestrial geophysical dynamics.
  • Optimising Gaia — that Gaia shaped the planet in a way that made it an optimal environment for life as a whole. Kirchner claimed that this was not testable and therefore was not scientific.

Of Homeostatic Gaia, Kirchner recognised two alternatives. "Weak Gaia" asserted that life tends to make the environment stable for the flourishing of all life. "Strong Gaia" according to Kirchner, asserted that life tends to make the environment stable, in order to enable the flourishing of all life. Strong Gaia, Kirchner claimed, was untestable and therefore not scientific.

Referring to the Daisyworld Simulations, Kirchner responded that these results were predictable because of the intention of the programmers — Lovelock and Watson, who selected examples which would produce the responses they desired.

Lawrence Joseph in his book "Gaia: the birth of an idea" argued that Kirchner's attack was principally against Lovelock's integrity as a scientist. Lovelock did not attack Kirchner's views for ten years, until his autobiography "Homage to Gaia", where he calls Kirchner's position sophistry . Lovelock and other Gaia-supporting scientists, however, did attempt to disprove the claim that the theory is not scientific because it is impossible to test it by controlled experiment. For example, against the charge that Gaia was teleological Lovelock and Andrew Watson offered the Daisyworld model (and its modifications, above) as evidence against most of these criticisms.

Lovelock was careful to present a version of the Gaia Hypothesis which had no claim that Gaia intentionally or consciously maintained the complex balance in her environment that life needed to survive. It would appear that the claim that Gaia acts "intentionally" was a metaphoric statement in his popular initial book and was not meant to be taken literally. This new statement of the Gaia hypothesis was more acceptable to the scientific community.

The accusations of teleologism were largely dropped after this conference.

Range of views

Some have found James Kirchner's suggested spectrum, proposed at the First Gaia Chapman Conference, useful in suggesting that the original Gaia hypothesis could be split into a spectrum of hypotheses, ranging from the undeniable (Weak Gaia) to the radical (Strong Gaia).

At one end of this spectrum is the undeniable statement that the organisms on the Earth have altered its composition. A stronger position is that the Earth's biosphere effectively acts as if it is a self-organizing system, which works in such a way as to keep its systems in some kind of "meta-equilibrium" that is broadly conducive to life. The history of evolution, ecology and climate show that the exact characteristics of this equilibrium intermittently have undergone rapid changes, which are believed to have caused extinctions and felled civilizations (see climate change).

Weak Gaian hypotheses suggest that Gaia is co-evolutive. Co-evolution in this context has been thus defined: "Biota influence their abiotic environment, and that environment in turn influences the biota by Darwinian process." Lovelock (1995) gave evidence of this in his second book, showing the evolution from the world of the early thermo-acido-philic and methanogenic bacteria towards the oxygen enriched atmosphere today that supports more complex life.

The weakest form of the theory has been called "influential Gaia". It states that biota minimally influence certain aspects of the abiotic world, e.g. temperature and atmosphere.

The weak versions are more acceptable from an orthodox science perspective, as they assume non-homeostasis. They state the evolution of life and its environment may affect each other. An example is how the activity of photosynthetic bacteria during Precambrian times have completely modified the Earth atmosphere to turn it aerobic, and as such supporting evolution of life (in particular eukaryotic life). However, these theories do not claim the atmosphere modification has been done in coordination and through homeostasis. Also such critical theories have yet to explain how conditions on Earth have not been changed by the kinds of run-away positive feedbacks that have affected Mars and Venus.

Biologists and earth scientists usually view the factors that stabilize the characteristics of a period as an undirected emergent property or entelechy of the system; as each individual species pursues its own self-interest, for example, their combined actions tend to have counterbalancing effects on environmental change. Opponents of this view sometimes reference examples of lives' actions that have resulted in dramatic change rather than stable equilibrium, such as the conversion of the Earth's atmosphere from a reducing environment to an oxygen-rich one. However, proponents argue these atmospheric changes improved the environment's suitability for life.

Some go a step further and hypothesize that all lifeforms are part of one single living planetary being called Gaia . In this view, the atmosphere, the seas and the terrestrial crust would be results of interventions carried out by Gaia through the coevolving diversity of living organisms. While it is arguable that the Earth as a unit does not match the generally accepted biological criteria for life itself ( Gaia has not yet reproduced, for instance; it still might spread to other planets through human space colonization and terraforming), many scientists would be comfortable characterizing the earth as a single "system".

Strong Gaia

A version called "Optimizing Gaia" asserts that biota manipulate their physical environment for the purpose of creating biologically favorable, or even optimal, conditions for themselves. "The Earth's atmosphere is more than merely anomalous; it appears to be a contrivance specifically constituted for a set of purposes" [7] . Further, "... it is unlikely that chance alone accounts for the fact that temperature, pH and the presence of compounds of nutrient elements have been, for immense periods, just those optimal for surface life. Rather, ... energy is expended by the biota to actively maintain these optima" [7] .

Another strong hypothesis is the one called "Omega Gaia" [24] . Teilhard de Chardin claimed that the Earth is evolving through stages of cosmogenesis, affecting the geosphere, biogenesis of the biosphere, and noogenesis of the noosphere, culminating in the Omega Point . Another form of the strong Gaia hypothesis is proposed by Guy Murchie who extends the quality of a holistic lifeform to galaxies. "After all, we are made of star dust. Life is inherent in nature." Murchie describes geologic phenomena such as sand dunes, glaciers, fires, etc. as living organisms, as well as the life of metals and crystals. "The question is not whether there is life outside our planet, but whether it is possible to have "nonlife".

There are speculative versions of the Gaia hypothesis, including versions in which it is held that the Earth is conscious or part of some universe-wide evolution such as expressed in the Selfish Biocosm hypothesis strain of a larger speculative Gaia philosophy. These extreme forms of the Gaia hypothesis, that the entire Earth is a single unified organism that is consciously manipulating the climate in order to make conditions more conducive to life, are metaphysical or mystical views for which no evidence exists, and which cannot be tested scientifically. Another strain which also goes further than science presently justifies, is the Gaia Movement, a collection of different organisations operating in different countries, but all sharing a concern for how humans might live more sustainably within the "living system".

Recent developments

Gaia Theory has developed considerably and in recent years both Lovelock's and Margulis's understanding of Gaia have gained some increased support as a potentially viable, testable scientific hypothesis or theory. [10] [25] . Margulis dedicated the last of eight chapters in her book, The Symbiotic Planet , to Gaia. She resented the widespread personification of Gaia and stressed that Gaia is "not an organism", but "an emergent property of interaction among organisms". She defined Gaia "the series of interacting ecosystems that compose a single huge ecosystem at the Earth's surface. Period." Yet still she argues, "the surface of the planet behaves as a physiological system in certain limited ways". Margulis seems to agree with Lovelock in that, in what comes to these physiological processes, the Earth's surface is "best regarded as alive". The book's most memorable "slogan" was actually quipped by a student of Margulis': "Gaia is just symbiosis as seen from space". This neatly connects Gaia theory to Margulis' own theory of endosymbiosis.

Second Gaia conference

By the time of the 2nd Chapman Conference on the Gaia Hypothesis, held at Valencia, Spain, on 23 June 2000, the situation had developed significantly in accordance with the developing science of Bio-geophysiology. Rather than a discussion of the Gaian teleological views, or "types" of Gaia Theory, the focus was upon the specific mechanisms by which basic short term homeostasis was maintained within a framework of significant evolutionary long term structural change.

The major questions were:

  • "How has the global biogeochemical/climate system called Gaia changed in time? What is its history? Can Gaia maintain stability of the system at one time scale but still undergo vectorial change at longer time scales? How can the geologic record be used to examine these questions?"
  • "What is the structure of Gaia? Are the feedbacks sufficiently strong to influence the evolution of climate? Are there parts of the system determined pragmatically by whatever disciplinary study is being undertaken at any given time or are there a set of parts that should be taken as most true for understanding Gaia as containing evolving organisms over time? What are the feedbacks among these different parts of the Gaian system, and what does the near closure of matter mean for the structure of Gaia as a global ecosystem and for the productivity of life?"
  • "How do models of Gaian processes and phenomena relate to reality and how do they help address and understand Gaia? How do results from Daisyworld transfer to the real world? What are the main candidates for "daisies"? Does it matter for Gaia theory whether we find daisies or not? How should we be searching for daisies, and should we intensify the search? How can Gaian mechanisms be investigated using process models or global models of the climate system which include the biota and allow for chemical cycling?"

In 1997. Tyler Volk argued that a Gaian system is almost inevitably produced as a result of an evolution towards far-from-equilibrium homeostatic states that maximise entropy production, and Kleidon (2004) agreed stating: "...homeostatic behavior can emerge from a state of MEP associated with the planetary albedo"; "...the resulting behavior of a biotic Earth at a state of MEP may well lead to near-homeostatic behavior of the Earth system on long time scales, as stated by the Gaia hypothesis." Staley (2002) has similarly proposed " alternative form of Gaia theory based on more traditional Darwinian principles... In [this] new approach, environmental regulation is a consequence of population dynamics, not Darwinian selection. The role of selection is to favor organisms that are best adapted to prevailing environmental conditions. However, the environment is not a static backdrop for evolution, but is heavily influenced by the presence of living organisms. The resulting co-evolving dynamical process eventually leads to the convergence of equilibrium and optimal conditions."

Third Gaia conference

A third international conference on the Gaia Theory, sponsored by the Northern Virginia Regional Park Authority and others, was held in October 2006 at the Arlington, VA campus of George Mason University. Lynn Margulis, Distinguished University Professor in the Department of Geosciences, University of Massachusetts-Amherst, and long-time advocate of the Gaia Theory, was a keynote speaker. Among many other speakers: Tyler Volk, Co-director of the Program in Earth and Environmental Science at New York University; Dr. Donald Aitken, Principal of Donald Aitken Associates; Dr. Thomas Lovejoy, President of the Heinz Center for Science, Economics and the Environment; Robert Correll, Senior Fellow, Atmospheric Policy Program, American Meteorological Society and noted environmental ethicist, J. Baird Callicott. James Lovelock, the theory’s progenitor, prepared a video specifically for the event.

This conference approached Gaia Theory as both science and metaphor as a means of understanding how we might begin addressing 21st century issues such as climate change and ongoing environmental destruction.

Gaia hypothesis in ecology

After much criticism, a modified Gaia hypothesis is now considered within ecological science basically consistent with the planet Earth being the ultimate object of ecological study. Ecologists generally consider the biosphere as an ecosystem and the Gaia hypothesis, though a simplification of that original proposed, to be consistent with a modern vision of global ecology, relaying the concepts of biosphere and biodiversity. The Gaia hypothesis has been called geophysiology or Earth System Science, which takes into account the interactions between biota, the oceans, the geosphere, and the atmosphere. To promote research and discussion in these fields an organisation, "Gaia Society for Research and Education in Earth System Science" was started.

An example of the change in acceptability of Gaia theories is the Amsterdam declaration of the scientific communities of four international global change research programmes — the International Geosphere-Biosphere Programme (IGBP), the International Human Dimensions Programme on Global Environmental Change (IHDP), the World Climate Research Programme (WCRP) and the international biodiversity programme DIVERSITAS — recognise that, in addition to the threat of significant climate change, there is growing concern over the ever-increasing human modification of other aspects of the global environment and the consequent implications for human well-being.

"Research carried out over the past decade under the auspices of the four programmes to address these concerns has shown that:

  • The Earth System behaves as a single, self-regulating system with physical, chemical, biological, and human components. The interactions and feedbacks between the component parts are complex and exhibit multi-scale temporal and spatial variability. The understanding of the natural dynamics of the Earth System has advanced greatly in recent years and provides a sound basis for evaluating the effects and consequences of human-driven change.
  • Human activities are significantly influencing Earth's environment in many ways in addition to greenhouse gas emissions and climate change. Anthropogenic changes to Earth's land surface, oceans, coasts and atmosphere and to biological diversity, the water cycle and biogeochemical cycles are clearly identifiable beyond natural variability. They are equal to some of the great forces of nature in their extent and impact. Many are accelerating. Global change is real and is happening now.
  • Global change cannot be understood in terms of a simple cause-effect paradigm. Human-driven changes cause multiple effects that cascade through the Earth System in complex ways. These effects interact with each other and with local- and regional-scale changes in multidimensional patterns that are difficult to understand and even more difficult to predict.
  • Earth System dynamics are characterised by critical thresholds and abrupt changes. Human activities could inadvertently trigger such changes with severe consequences for Earth's environment and inhabitants. The Earth System has operated in different states over the last half million years, with abrupt transitions (a decade or less) sometimes occurring between them. Human activities have the potential to switch the Earth System to alternative modes of operation that may prove irreversible and less hospitable to humans and other life. The probability of a human-driven abrupt change in Earth's environment has yet to be quantified but is not negligible.
  • In terms of some key environmental parameters, the Earth System has moved well outside the range of the natural variability exhibited over the last half million years at least. The nature of changes now occurring simultaneously in the Earth System, their magnitudes and rates of change are unprecedented. The Earth is currently operating in a no-analogue state."

Sir Crispin Tickell in the 46th Annual Bennett Lecture for the 50th Anniversary of Geology at the University of Leicester in his recent talk "Earth Systems Science: Are We Pushing Gaia Too Hard?" stated "as a theory, Gaia is now winning." [26]

He continued "The same goes for the earth systems science which is now the concern of the Geological Society of London (with which the Gaia Society recently merged). Whatever the label, earth systems science, or Gaia, has now become a major subject of inquiry and research, and no longer has to justify itself."

These findings would seem to be fully in accord with the Gaia theory. Despite this endorsement, the late W. D. Hamilton, one of the founders of modern Darwinism, whilst conceding the empirical basis of the planetary homeostatic processes on which Gaia is based, states that it is a theory still awaiting its Copernicus. The homeostatic nature of the global system has been recognized as a consequence of the 2 nd law of thermodynamics. [27] In their comprehensive book on the thermodynamics of life, Eric D. Schneider and Dorion Sagan argue that Gaia belongs to a class of complex thermodynamic systems, not just living ones, that are naturally purposeful; and that life optimizes rather than maximizes entropy production. [28]

The Revenge of Gaia

In James Lovelock's 2006 book, The Revenge of Gaia , he argues that the lack of respect humans have had for Gaia, through the damage done to rainforests and the reduction in planetary biodiversity, is testing Gaia's capacity to minimize the effects of the addition of greenhouse gases in the atmosphere. This eliminates the planet's negative feedbacks and increases the likelihood of homeostatic positive feedback potential associated with runaway global warming. Similarly the warming of the oceans is extending the oceanic thermocline layer of tropical oceans into the Arctic and Antarctic waters, preventing the rise of oceanic nutrients into the surface waters and eliminating the algal blooms of phytoplankton on which oceanic foodchains depend. As phytoplankton and forests are the main ways in which Gaia draws down greenhouse gases, particularly carbon dioxide, taking it out of the atmosphere, the elimination of this environmental buffering will see, according to Lovelock, most of the earth becoming uninhabitable for humans and other life-forms by the middle of this century, with a massive extension of tropical deserts.

Given these conditions, Lovelock expects human civilization will be hard pressed to survive. He expects the change to be similar to the Paleocene-Eocene Thermal Maximum when atmospheric concentration of CO 2 was 450 ppm. At that point the Arctic Ocean was 23 °C and had crocodiles in it, with the rest of the world mostly scrub and desert. He says of sustainable development and renewable energy that it came "200 years too late" and that more effort should go into adaptation, including more use of fission. He likens the Kyoto Protocol to the Munich conferences that failed to prevent World War II, including the likelihood that the disaster will cause people to come together in common cause. "We have been through no less than seven of these events as humans...comparable in extent to the change" likely to be wrought by global warming.

He claims that Gaia's self-regulation will likely prevent any extraordinary runaway effects that wipe out life itself, but that humans will survive and be "culled and, I hope, refined."

According to James Lovelock, by 2040, the world population of more than six billion will have been culled by floods, drought and famine. Indeed [t]he people of Southern Europe, as well as South-East Asia, will be fighting their way into countries such as Canada, Australia and Britain . [29]

" By 2040, parts of the Sahara desert will have moved into middle Europe. We are talking about Paris - as far north as Berlin. In Britain we will escape because of our oceanic position." [29]
" If you take the Intergovernmental Panel on Climate Change predictions, then by 2040 every summer in Europe will be as hot as it was in 2003 - between 110F and 120F. It is not the death of people that is the main problem, it is the fact that the plants can't grow — there will be almost no food grown in Europe. " [29]
" We are about to take an evolutionary step and my hope is that the species will emerge stronger. It would be hubris to think humans as they now are God's chosen race. " [29]

Lovelock believes it is too late to repair the damage. [29]

Influences of the Gaia hypothesis

Scientific literature.

Fritjof Capra, in his fourth book, The Web of Life, used Gaia theory to explain the complications and interconnections in the web of life.

Stephan Harding, a student of Lovelock, has written a book, Animate Earth: Science, Intuition, and Gaia .

John Gribben and Mary Gribben have written a book "James Lovelock - In Search of Gaia" and published by Princeton University Press. ISBN 978-0-691-13750-6. Reviewed briefly in EOS (Trans, AGU), Vol. 90, No. 20, 19 May 2009.

An oratorio by American composer Nathan Currier called Gaian Variations was premiered on Earth Day 2004 at Lincoln Center by the Brooklyn Philharmonic, using texts of James Lovelock, Loren Eiseley and Lewis Thomas.

A Heavy Metal/ Folk Rock band from Spain called Mago de Oz has also composed two songs "Gaia" and "La Venganza de Gaia" (Gaia's Revenge) which talk about man and his actions, altering the natural balance on earth. These songs claim that all bad things done to Gaia, will be brought upon man as well, given that we are all part of the same living entity. The Disco Biscuits, from Philadelphia, mention Gaia many times as the central theme in their song "Jigsaw Earth" on their 2002 album Senor Boombox

On his 1997 CD release Hourglass , Popular American songwriter James Taylor included a song called "Gaia".

The Melodic Death metal band At the Throne of Judgement, on their record "The Arcanum Order", includes a song "Martyrdom, Ruin of Gaia"

In 2009, Kevadbänd has reflected Gaia hypothesis in its hit song "Kasvaja" ("Tumor"), which states that the Gaia organism is suffering from lethal tumor: the human race

American heavy metal band God Forbid included a song entitled "Gaia (The Vultures)" on their 2009 release "Earthsblood".

Movies and television

The film Virus features a cyborg that believes humanity to be a virus that has infected its host organism, Earth.

The South Park episode Lice Capades addresses the Gaia hypothesis from an ironic standpoint – when one louse suggests that the planet (a child's head) is alive, another louse responds with "If the planet was alive, would it feel this?" and shoots the boy's head – the impact being so minute the boy barely notices.

Edge of Darkness a British television drama serial, produced by BBC Television in association with Lionheart Television International and originally broadcast in six fifty-five minute episodes in late 1985.

In Final Fantasy: The Spirits Within, a sci-fi movie, Dr. Sid and his assistant Aki are fierce promoters of the Gaia Theory. Though, in the film, "Gaia" is in reference to the underlying life force within the planet, very similar to the lifestream found in Final Fantasy VII.

The series Eureka Seven features a planet where coral structure engulfed the planet making it a super organism.

James Cameron's Avatar features a Gaia-like network on the planet of Pandora, in which all the organisms have a biological ability to "connect" and share mental communication. This is perhaps a metaphor for the interconnections and systems between organisms and the environment on Earth. The Gaia-like system in Avatar is referred to as Eywa, a goddess which the natives worship as a mother earth figure. This reference back to earth and the Gaia Hypothesis is further supported by a scene from the move where Jake Sully's Avatar, while "praying" to Eywa, says that they (referring to Earthlings) "Killed their mother".

A number of works of fiction use the Gaia hypothesis as a central part of the plot. In two of his science fiction novels, Foundation's Edge (1982) and Foundation and Earth (1984), Isaac Asimov describes the planet Gaia as one on which all things, living and inanimate, are taking part in a planetary consciousness to an appropriate measure. In Asimov's story Gaia strives for an even greater superorganism that it calls Galaxia, and that comprises the whole galaxy.

In Lovelock (1994), a novel by Orson Scott Card & Kathryn H. Kidd, Gaiaology is a fully fledged interdisciplinary science which will soon be put to use by the Earth's first interstellar colony ship. Assuming the target planet will need terraforming, the job of the ship's Gaiaologist will be to integrate the terrestrial species needed for the colonists' survival with the planet's existing ecology. The Gaiaologist's "Witness", a form of assistance animal whose job it is to record every waking moment in the life of such a prominent member of society, is the central character of the book, an enhanced Capuchin monkey named after Lovelock.

The Gaia hypothesis is used extensively by Brian Aldiss in his Helliconia Trilogy, where the planets of Helliconia and, to a lesser extent, Earth, are presented as the main characters in a story spanning the rise and fall of civilizations as influenced by Helliconia's 2,500-year-long cycle of seasons.

The Gaia hypothesis was also used as a central theme in the novel Portent , by James Herbert, in which Lovelock is mentioned by name.

David Brin's novel Earth discusses the Gaia hypothesis and features a fictional Gaia ecological movement.

The plot of the novel Gaia by David Orrell involves a Gaian cult that intends to purge the Earth of humanity by spreading a bioengineered disease.

American poet, writer and Deep Ecology activist Gary Snyder has a chapter of poems called "Little Songs for Gaia" in his collection of poetry "Axe Handles" (1983).

Maxis has specifically named the Gaia hypothesis and Lovelock as inspirations for their 1990 game, SimEarth.

The 1997 console role-playing game, Final Fantasy VII features a paradigm of so-called Lifestream, also appearing in the 2001 film, Final Fantasy: The Spirits Within as the 'Dr. Sid's Gaia Theory' (these theories look almost identical due to the same scenario writers, Hironobu Sakaguchi and Kazushige Nojima). According to it, all living beings are given some 'spiritual energy' by the spirit of the Planet (Gaia) prior to birth, live out their lives, and then die, with the energy then returning to the Planet. The entire planet (or Gaia) is really a single living organism with its own consciousness and will.

The 2008 Sega title Sonic Unleashed contains the character Eggman (Sonic's arch nemesis), fueled with the desire to control the Earth's 'Gaia force' and attempting to crack open the planet to unleash an Evil Entity confined within the Earth's core. Eggman also claims to have studied the 'Gaia Manuscripts'.

The 1999 turn-based strategy PC game, Sid Meier's Alpha Centauri , features a living (and eventually sentient) planet in the Alpha Centauri star system. One of the games factions is named "Gaia's Stepdaughters", a group of environmentalists who believe in living with the planet rather than trying to tame or destroy it.

Pop culture

The notion of Gaia has been applied to the networked society and the globalized Internet by cultural theorist Dr. Michael Strangelove , "Confronted with the inaccessibility of our physical frontiers, my generation has turned inward and discovered two new immanent and infinite frontiers. These new frontiers of the next millennium are the uncensored, distributed self, and cyberspace —the location of the virtual self/community— Electric Gaia." [30]

  • Autopoiesis
  • Biocoenosis
  • Blue marble
  • Earth Science
  • Environmentalism
  • Gaia Thesis
  • Geophysiology
  • Global brain
  • Global Consciousness Project
  • James Kirchner
  • Medea hypothesis
  • Permaculture
  • Technogaianism
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  • Lovelock, James. The Independent . The Earth is about to catch a morbid fever, 16 January 2006.
  • Kleidon, Axel (2004). "Beyond Gaia: Thermodynamics of Life and Earth system functioning". Climatic Change 66 (3): 271–319. doi:10.1023/
  • Lovelock, James (1995). The Ages of Gaia: A Biography of Our Living Earth . New York: Norton. ISBN 0-393-31239-9.
  • Lovelock, James (2000). Gaia: A New Look at Life on Earth . Oxford: Oxford University Press. ISBN 0-19-286218-9.
  • Lovelock, James (2001). Homage to Gaia: The Life of an Independent Scientist . Oxford: Oxford University Press. ISBN 0-19-860429-7.
  • Lovelock, James (2006), interviewed in How to think about science , CBC Ideas (radio program), broadcast January 3, 2008
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  • Staley M (September 2002). "Darwinian selection leads to Gaia". J. Theor. Biol. 218 (1): 35–46. doi:10.1006/jtbi.2002.3059. PMID 12297068. .
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  2. Gaia Hypothesis (ANIMA MUNDI)

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  1. Gaia hypothesis

    The Gaia hypothesis ( / ˈɡaɪ.ə / ), also known as the Gaia theory, Gaia paradigm, or the Gaia principle, proposes that living organisms interact with their inorganic surroundings on Earth to form a synergistic and self-regulating, complex system that helps to maintain and perpetuate the conditions for life on the planet.

  2. Gaia hypothesis

    Gaia hypothesis, model of the Earth in which its living and nonliving parts are viewed as a complex interacting system that can be thought of as a single organism. Developed c. 1972 largely by British chemist James E. Lovelock and U.S. biologist Lynn Margulis, the Gaia hypothesis is named for the Greek Earth goddess. It postulates that all living things have a regulatory effect on the Earth ...

  3. Gaia Hypothesis

    The Gaia hypothesis postulates that the Earth's surface is maintained in a habitable state by self-regulating feedback mechanisms involving organisms tightly coupled to their environment. The concept is based on several observations: • The atmosphere is in an extreme state of thermodynamic disequilibrium owing to the activities of life, yet aspects of its composition are remarkably stable.

  4. PDF Gaia hypothesis

    Gaia hypothesis. The Gaia hypothesis, also known as Gaia theory or Gaia principle, proposes that all organisms and their inorganic surroundings on Earth are closely integrated to form a single and self-regulating complex system, maintaining the conditions for life on the planet. The scientific investigation of the Gaia hypothesis focuses on ...

  5. Climate

    The Gaia hypothesis. The notion that the biosphere exerts important controls on the atmosphere and other parts of the Earth system has increasingly gained acceptance among earth and ecosystem scientists. While this concept has its origins in the work of American oceanographer Alfred C. Redfield in the mid-1950s, it was English scientist and inventor James Lovelock that gave it its modern ...

  6. Scientists finally have an explanation for the 'Gaia puzzle'

    Consequently the Gaia hypothesis has typically been considered as interesting but speculative - and not grounded in any testable theory. Selecting for stability We think there is finally an ...

  7. Gaia Hypothesis

    The Gaia hypothesis is a recent and highly controversial theory that views Earth as an integrated, pseudo-organismic entity and not as a mere physical object in space. The Gaia hypothesis suggests that organisms and ecosystems on Earth cause substantial changes to occur in the physical and chemical nature of the environment, in a manner that ...

  8. Gaia philosophy

    Gaia philosophy (named after Gaia, Greek goddess of the Earth) is a broadly inclusive term for relating concepts about, humanity as an effect of the life of this planet.. The Gaia hypothesis holds that all organisms on a life-giving planet regulate the biosphere in such a way as to promote its habitability. Gaia concepts draw a connection between the survivability of a species (hence its ...

  9. Gaia hypothesis

    Gaia hypothesis. The Gaia hypothesis is a class of scientific models of the geo-biosphere in which life as a whole fosters and maintains suitable conditions for itself by helping to create a favorable environment on Earth for its continuity. The Gaia hypothesis was developed by atmospheric scientist and chemist Sir James Lovelock.

  10. PDF The Gaia Hypothesis: Fact, Theory, and Wishful Thinking

    to assess the current, more focused Gaia hypothesis, and to outline the difficulties that it poses. Gaia contains elements of fact, theory, and wishful thinking. One part of Gaia that is clearly fact is the recognition that Earth's organisms have a significant effect on the physical and chemical environment. Biogeochemists have devoted

  11. Gaia theory: is it science yet?

    Gaia hypothesis: the original version — the Earth's organisms regulate the physical and chemical components of the earth system so as to maintain the planet as an optimal habitat for life.

  12. James Lovelock at 100: the Gaia saga continues

    Lovelock's Gaia theory states that, for much of the past 3.8 billion years, a holistic feedback system has played out in the biosphere, with life forms regulating temperature and proportions of ...

  13. Who was James Lovelock, what is Gaia theory, and why does it matter

    The scientist credited with inventing Gaia theory has been celebrated by everyone from the New-Age movement to nuclear power advocates. But what is the late James Lovelock's lasting legacy to science?

  14. James Lovelock

    Gaia hypothesis. James Lovelock (born July 26, 1919, Letchworth Garden City, Hertfordshire, England—died July 26, 2022, Abbotsbury, Dorset) English chemist, medical doctor, scientific instrument developer, and author best known for the creation and promulgation of the Gaia hypothesis, an idea rooted in the notion that all life on Earth is ...

  15. Global Change Lecture Notes: The Gaia Hypothesis

    "The Gaia hypothesis states that the lower atmosphere of the earth is an integral, regulated, and necessary part of life itself. For hundreds of millions of years, life has controlled the temperature, the chemical composition, the oxidizing ability, and the acidity of the earth's atmosphere" ...

  16. Gaia Theory in a Nutshell

    Gaia theory is the idea that life regulates the Earth's atmosphere and climate through its metabolic processes. Learn how James Lovelock and Lynn Margulis developed this theory, how it challenges Darwinian biology, and how it relates to complexity science.

  17. What is the Gaia hypothesis introduced by James Lovelock?

    The Gaia hypothesis states that the Earth's surface is maintained in a habitable state by self-regulating feedback mechanisms involving organisms that are closely related and tightly coupled to ...

  18. The Gaia Hypothesis: What Does It Mean for Life on Earth?

    The Gaia hypothesis continues to be popular in more spiritual circles, but there is little scientific consensus on its validity. One reason is simply that the Earth is so complex, and the Gaia theory so broad, that it's virtually impossible to definitively prove or disprove the hypothesis.

  19. Gaia Hypothesis

    The Gaia hypothesis through the Daisyworld simulations proved that the percentage of black daisies in comparison to white ones will continuously change so both could thrive. This further shows that competition and even with a limited range of conditions like on the planet Daisyworld can also support life with stabilized temperatures.

  20. PDF James Lovelock's Gaia hypothesis: ''A New Look at Life on Earth'' for

    The Gaia hypothesis was altogether considered to be an extreme form of holism and of naively benevolent views of nature: a metaphor at best, pseudo-scientific mysticism at worse.13 What is particularly remarkable when looking at Gaia's reception in

  21. Gaia Hypothesis

    Gaia Hypothesis. The Gaia hypothesis is an ecological hypothesis proposing that the biosphere and the physical components of the Earth (atmosphere, cryosphere, hydrosphere and lithosphere) are closely integrated to form a complex interacting system that maintains the climatic and biogeochemical conditions on Earth in a preferred homeostasis.

  22. Gaia

    The Gaia Hypothesis. The Gaia Hypothesis is a recent thought model that was partly invented by the British scientist James Lovelock (1919-2022). It proposes that the Earth functions as a single organism that helps all living things survive. All living beings act as a single harmonious entity to regulate Earth's climate, food sources, vegetation ...

  23. The Gaia Hypothesis

    The theory you asked about is known as the "Gaia Hypothesis". The Gaia hypothesis has both scientific and philosophical components. Gaia is theorized to be a living entity that is greater than the sum of all the living and non-living aspects of the Earth. In proposing this theory, James Lovelock sought to explain the many complex natural ...